Combination radiant and convection heater



Dec. 13, 1927. 1,652,686

J. SCHOENFELD COMBINATION RADIANT AND CONVECTION HEATER Filed April 15. 1925 2 Shets-Sheet 1 mum Dec. 13, 1927. 1,652,686

J. SCHOENFELD COMBINATION RADIANT AND CONVECTION HEATER Filed April-15, 1925 2 Sheets-Sheet 2 Patented Dec. 13, 1927.

UNITED STATES 1,652,686 PATENT OFFICE.

JOSEPH SCHOENFELD, OF ALAMEDA, CALIFORNIA, ASSIGNOB TO THE MAGNA VOX COMI- PANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF ARIZONA.

- COMBINATION RADIANT AND CONVECTION HEATER.

Application filed April 18 1925. Serial No. 22,621

This invention relates to electric heaters, and especially to a combined radiant and convection electric heater.

The object of the present myention 1s to generally improve and simplify the construction and operation of electric heaters, to provide a heater which lscapable of transmitting heat either by radiation or convection, or by the combined action of both, and further, to provide means whereby the amount of heat transmitted by radiation or convection may be regulated.

One form which the electrlc heater may assume is illustrated in the accompanylng drawings, in which Fig. 1 is a front view of the heater,

Fig. 2 is a plan view partly 1n section;

Fig. 3 is a rear view of the heater;

Fig. i is a central vertical sectional view taken on line sir-4: of Fig. 1;

Fig. 5 is a diagrammatic v1ew sh0w1ng the heating elements and the switch controlling the circuits therefor.

Referring to the drawings in detail, particularly Figs. 1 and 2, A indicates a base member supported by a pair of front legs 2-2 and a pair of rear legs 33. Mounted on the base section is a casing generally indicated at B, and supported on top of the casing is a cover section G, in which is formed a plurality of air outlet openings generally indicated at 4. The casing proper consists of a front plate 5, a rear plate 6, and a pair of end plates 7-E. A chamber is formed between the plates 5, 6, and 7--7, and this chamber is open at the top and bottom, the object being to permit air to circulate freely through the chamber in an outward direction. That is, the base section is open to permit air to freely enter the chamber, and the cover plate G is provided with openings 4: to permit the air to freely escape. Mounted within the chamber and suitably secured to the base and the top section is a frame generaly indicated at 8. Supported on the frame is a plurality of electric resistance elements such as shown at 9. These elements are divided into two groups, 11 and 12, the heating elements 11 and 12 serving the function of heating the air in the chamber and thereby inducing a continuous upward circulation of air. The front plate 5 is bent or shaped with a die to form. a plurality of grooves or channels generally indicated a it Th gr es ert n f m end to end of the plate, and they are substantlally parabolic in cross-section. Heating elements such as shown at 14 are disposed one in each groove, and will hereinafter be referred to as the radiant elements, while the heating elements 11 and 12 will be referred to as air-heating elements. The plate 5 serves two functions, first, that of reflectmg the heat and light rays emitted by the heating elements 1%; and secondly, that of heating the airchamber. The front portion of plate 5 is covered with a reflecting substance, and it is for this reason that most of the heat and light rays emitted by theelements 14. are projected in the form of radiant energy. A certain amount of the heat is, however, absorbed by radiation and conduction, and plate 5 thus becomes heated. This heat is transferred by convection to the air passing through the interior chamber, and it may therefore be stated that the elements 14 serve two functions; first that of producing radiant energy, and secondly that of heating the air by convection.

A switch generally indicated at D is pro" vided for the purpose of regulating the flow of electric current through the several heating elements. The switch is diagrammatically illustrated in Fig. 5, and it is provided with a switch arm 15 and four contacts indicated at 16, 17, 18 and 19. Con tact 16 is connected through a wire 20 with the heating elements 11 and 12, and also with the radiant elements 14, these lastnamed elements being in turn connected with the ground or return circuit, as indicated at 21. The incoming current enters at 22, passes through wire 23, switch arm 15, and then through the contact with which the switch arm aligns. Contact 17 is connected with a wire 24, and this connects with the central portion of the heating elements 11 and 12. Contact 18 is connected with a wire 25, and this is connected with the lower end of the heating elements 11. When a switch is arranged and connected in the manner shown in Fig. 5, it is possible to ass all of the current through the radiant e ements only if desired. It is also possible to pass the current through one-half the heating elements and then through the radiant elements, by connecting them in series; or it is possible to pass the current through all of the elements by connecting them all in series. if the switch arm 15 connects wlth contact its 16 the current will enter through wire 22 and will pass throu h the switch arm and contact 16, and then wire 20, which connects with the elements 14. These are connected in series, and are also connected with the return wire 21. In other words, when engagement is made with contact 16, all of the current will flow through the radiant elements, and substantially all the heat roduced will be projected radiantly. If it is desired to heat the air partially by convection and partially by radiation, the switch arm 15 is swung into engagement with contact 17. The current entering wire 22 will then pass through the switch arm 15, contact 17, and the wire 24. It will then pass through'the heating elements 12, and will then pass through wire and the radiant elements 14. In other words, in this position of the switch, a series connection is made between half of the heating elements and all of the radiant elements, and heat will be produced both by radiation and by convection. If it is desired to transmit all of the heat by convection, switch arm 15 is moved into engagement with contact 18. The current will then ass through wire 25 and will then flow through the heating ele-- ments 11 and 12 and the radiant elements 14. In other Words, a series connection will be made between all of the elements and practically all heat will be transmitted by convection, as the radiant elements will assume such a low temperature that the heat generated will be transmitted more by convection than by radiation. The induced air flow through the air-circulating chamber will be increased, as both heating elements 11 and 12 are operating. It is for this reason 1,es2,eee

that practically all heat will be transmitted by convection.

From the foregoing, it will be seen that a heater has been provided in which electric current may be converted into radiant eneigy" only if desired. Also, that the current may be transmitted both by radiation and convection, and that all of the current may be converted into heat and transmitted to the airby convection. While certain features of the resent invention are more or less specifical y illustrated, I wish it understood that various changes may be made within the scope of the appended claim, and similarly, that the materials and finish of the several parts of the heater ma be such as the experience and judgment 0 the manufacturer may dictate.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

An electric heater comprising a vertically disposed substantially rectan lar shaped casing formed of a front plate i dving an exterior reflecting surface formed thereon, a rear plate and a pair of end plates, said plates forming a chamber open at the top and bottom, two sets of electric heating elements disposed within the chamber and causing an upward flow of air through the chamber, electric heating elements disposed in front of the reflector, a switch, and means actuated by the switch for directing the current through the last-named elements only, or throu h the last-named elements and onehalf of t e first-named elements in series, or through all of the elements in series.

JOSEPH SCHOENFELD. 

